The long-term goal of the proposed research is to develop a rapid method of assessing the presence and progress of glaucoma -- a method which could be useful both for diagnosis and for evaluating progression and for response to treatment. The test will be objective, not requiring a patient to perform tasks, and will evaluate the status of substantial areas of retina in a single test. The immediate goal is to develop a new method of testing for glaucomatous damage, using the pupillary light reflex. The specific steps in reaching this goal are: (1) A rapid method will be developed for assessing the comparative sensitivity of retinal regions of substantial size. (2) The extent of variation of the test results in normal subjects will be determined. Within-subject variation will be determined to assess the stability of the testing method. Between-subject variation will be determined to assess the range of variation in normals. (3) The sensitivity of the test will be assessed, using natural, quantifiable asymmetries in normal retinal topography. This will provide information on the relationship between the extent of a defect and the results on the test. Together with the variability results from "2", this should provide an estimate of the function relating the extent of a retinal defect to its detectability. (4) The performance of the test will be assessed, using a group of patients who have substantial visual field loss. For glaucoma patients, the stimuli will be designed to exploit current knowledge of typical patterns of retina affected by glaucomatous damage. This will permit comparison of results from conventional visual fields with results of the pupillometric test. (5) The performance of the test will be assessed, using a group of patients with moderate glaucomatous loss. This will permit evaluation of the test on patients with less obvious field defects, moving the testing towards use in evaluating glaucoma suspects. The relationship between the results of the test and the severity of the glaucomatous loss will be studied to determine the power of the test to provide useful information in a clinical setting.